1. Field of the Invention
The invention relates in general to a driving method, and more particularly to a method for driving a movable component of a hardware device.
2. Description of the Related Art
Among various computer peripherals, the optical drive has become an essential equipment for users of the personal computer. Presently, the controlling method for loading and unloading the tray is the identical procedure for every optical drive. However, giving a fixed force to the tray with varied friction force may cause unsteady operation. When the friction force decreases, the tray can easily go beyond the designated position and get stuck, generating noise due to the tray vibration. When the friction force increases, the tray halts before arriving at the designated position, which may bring the user great inconvenience. Therefore, for the manufacturers of optical drives, the approach to make the operation of loading and unloading the tray smooth becomes a crucial technique.
Referring to FIG. 1, the inner structure of the optical drive is shown. In general, several stoppers 130 are disposed on the casing of the optical drive 100 to absorb the shock from the tray 110. When loading the tray 110, the stoppers 130 absorb the shock as the tray 110 hits the rear of the casing. When unloading the tray 110, the stoppers 150 prevent the tray 110 from coming off the casing. It takes more force to make the tray 110 move from rest by overcoming the maximum static friction force than to keep it moving once it is in motion. Before arriving at the designated position, the tray 110 makes contact with a switch to stop the motor from continuing to provide the tray 110 with any driving force. The tray 110 subsequently keeps on moving along the guides 120. If the tray 110 is still in motion when arriving at the designated position, the tray 110 come to easily shake and possibly cause damage to the components. Since it requires forces of two different strengths to push the tray 110, it therefore requires two different voltages for the motor to provide two different forces. At first, the motor provides a larger former force according to a larger first voltage to drive the tray 110 to move a former distance and then provides the smaller latter force according to a smaller second voltage to drive the tray 110 to move a latter distance. After the smaller latter force drives the tray 110 to move the latter force, the tray 110 makes contact with a switch to stop the motor from continuing to provide the tray 110 with any force. The tray 110 keeps on moving due to its inertia. However, the kinetic friction force between the tray 110 and the guide 120 opposes the motion of the tray 110. By means of a design, the tray 110 gradually slows down and finally stops at the designated position as soon as the tray 110 touches the stoppers 130 or 150.
Referring to FIG. 2A, the diagram shows the method for driving the tray of the optical drive by adjusting the voltage. The motor provides a larger former force according to a larger first voltage V1 to drive the tray 110 to move for a period t1 and then provides the smaller latter force according to a smaller second voltage V2 to drive the tray 110 to move for a period t2. Subsequently, the tray 110 keeps on moving due to its inertia until the tray 110 arrives at the designated position. Referring to FIGS. 2B to 2D, the tray 110 at rest is driven by voltage V1 to move a former distance S1 for a period t1 and then is driven by voltage V2 to move a latter distance S2 for a period t2. Once the tray 110 touches off a switch sw, the motor stops providing the tray 110 with any force. The tray 110 keeps on moving a sliding distance Ss due to its inertia and finally comes to a halt, as shown in FIG. 2E.
In the above-mentioned driving method, the periods t1 and t2, for which the motor drives the tray 110 with the first voltage V1 and second voltage V2 respectively, might produce the following problems:
1. The method for driving the tray 110 is the identical procedure for every optical drive regardless of the differences produced by the manufacturing process, such as the differences in the friction force between the tray 110 and the guide 120, for example.
2. The components of the optical drive will be worn out after being used for a period of time, and the friction forces among the components will change as well. Thus, after a period of time, the original driving method might not be able to drive the tray 110 to stop at the designated position perfectly.
3. The friction force between the tray 110 and the guide 120 varies with the operation condition of the optical drive. For example, the identical driving method fails to fit in with both the vertical placement and horizontal placement of the optical.
It is impossible that the identical driving method suits every different situation that is listed above. The tray 110 might halt before arriving at the designated position. The tray 110 might hit the stoppers 150 with a remained speed and therefore generate noise due to the tray vibration, and damage other components.